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J Neurosurg Spine 2018 Dec 14:1-9. Epub 2018 Dec 14.

OBJECTIVEC1-2 is a highly mobile complex that presents unique surgical challenges to achieving biomechanical rigidity and fusion. Posterior wiring methods have been largely replaced with segmental constructs using the C1 lateral mass, C1 pedicle, C2 pars, and C2 pedicle. Modifications to reduce surgical morbidity led to the development of C2 laminar screws. Read More

A 5-year-old boy with a chromosome-9 abnormality and multiple external and visceral malformations was found in cardiopulmonary arrest during a regular visit to the hospital; he did not respond to cardiopulmonary resuscitation and died. An odontoid process fracture and calcification and fibrosis of the muscles around the superior cervical vertebra were observed during the autopsy. Postmortem computed tomography revealed an anterior dislocation of the atlas; odontoid synchondrosis fracture; and delayed, incomplete bony fusion of the odontoid process relative to his age. Read More

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Atlanto-axial instability (AAI) is a congenital or developmental condition that leads to instability/subluxation of the atlantoaxial joint. This study is performed to determine anatomic feasibility of trajectory L and help select an optimal screw trajectory in treating patients with AAI with a narrow C1 posterior arch. Sixty patients who underwent cervical three dimensional-computed tomography (3D-CT) were chosen from the hospital's picture archiving and communication system (PACS). Read More

Objective: The main purpose of this study was to define criteria to systemically describe craniovertebral junction (CVJ) anomalies and to report the prevalence of CVJ anomalies in small breed dogs with and without atlantoaxial instability (AAI).

Methods: Retrospective multicentre matched case-control study evaluating magnetic resonance imaging and computed tomographic images of small breed dogs with and without AAI for the presence of CVJ anomalies.

Results: One hundred and twenty-two dogs were enrolled (61 with and 61 without AAI). Read More

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Department of Orthopedics, Peking University Third Hospital, Beijing, China.

Objective: Atlantoaxial stabilization procedures in high-riding vertebral artery (HRVA) cases are challenging. C2 translaminar screws are rigid and pose no risk to the vertebral artery. The aim of this study was to present clinical outcomes of atlantoaxial dislocation combined with HRVA using C2 translaminar screws. Read More

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Background: Atlantoaxial dislocation usually results from hyperextension trauma and is almost always accompanied by odontoid fracture and neurological symptoms. In most cases, patients with atlantoaxial dislocation die instantly. This is a rare report of posterior atlantoaxial dislocation without fracture and neurological symptoms effectively treated by transoral-posterior approach surgery, and only eleven similar cases have been previously reported. Read More

Giant cell tumor (GCT) or osteoclastoma is a benign, locally aggressive tumor with a tendency to recur. Involvement of the axial skeleton is very rare and majority of them are seen in the sacrum. The authors report a rare case of a 19-year-old female who presented with a C2 dens GCT with a pathological fracture and atlantoaxial dislocation. Read More

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In addition to involvement of small peripheral joints, the cervical spine is the second most affected body region in rheumatoid arthritis (RA). Due to improvement of pharmaceutical treatment in recent years, new data show that there is a decreasing prevalence of cervical involvement; however, depending on the severity of cervical lesions surgical treatment still plays an important role. The sequelae of involvement of the cervical spine are craniocervical and atlantoaxial instability, which can cause severe pain, neural deficits and even death. Read More

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Priorov National Medical Research Center of Traumatology and Orthopedics, Moscow, Russia.

Treatment of patients with atlantoaxial instability caused by various diseases of the skull base and craniovertebral junction combined with ventral compression of the brainstem is a complex issue that is ambiguously resolved in different ways. We present a case of stepped treatment, the most important component of which was successful transoral removal of an aggressive aneurysmal bone cyst of the CII vertebra with anterior CI-CIII segment stabilization using an individual system, which was performed through the same approach.

Clinical Case: A 31-year-old male patient presented with destruction of the CII body and odontoid process affected by an aggressive aneurysmal bone cyst causing disintegration of the CII posterior wall and odontoid process, which clinically manifested by constricted motion and pain in the cervical spine. Read More

Authors:

Purpose: We present a rare case of atlantoaxial instability as a result of bone erosions in a patient with ankylosing spondylitis and review the literature. We describe the radiographic characters, pathology and treatment of the case, hoping to shed light on the rare clinical manifestation.

Methods: We present a case of a 36-year-old male with an 8-year history of ankylosing spondylitis with a progressive neck pain, low back pain, hand numbness and motion limitation of neck. Read More

Retroodontoid pseudotumor (ROP) is a nonneoplasic lesion of unknown etiology, commonly associated with inflammatory conditions, and the term of pannus is usually used. Less frequently, ROP formation can develop with other noninflammatory entities, with atlantoaxial instability as most accepted pathophysiological mechanism for posttraumatic or degenerative ROP. As it can clinically and radiologically mimic a malignant tumor, it is paramount for the radiologist to know this entity. Read More

Objective: The implications of diagnosis and treatment of central or axial atlantoaxial dislocation (CAAD) as a cause of symptoms of cervical myelopathy are evaluated.

Methods: This is a report of a series of 5 patients who presented with the primary symptoms of spasticity and motor weakness and paresthesias in all the limbs. There was no evidence of any significant compression of the dural tube or neural structures at the craniovertebral junction. Read More

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Background: An anomalous vertebral artery is not a deterrent for posterior C1-C2 joint manipulation and reduction of atlantoaxial dislocation (AAD). However, presence of an incidental aneurysm in the aberrant segment of artery with concurrent AAD adds to the surgical challenge.

Purpose: Children with trisomy 21 are at a greater risk for craniocervical junction instability than the general population. These children frequently require administration of anesthesia due to surgical (including otolaryngological) interventions and are at risk for neurological injury. We reviewed the current literature describing iatrogenic neurological injury in children with trisomy 21 undergoing anesthesia in order to facilitate the development of safety recommendations. Read More

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OBJECTIVE To retrospectively evaluate the epidemiological and morphological features and outcome of surgical treatment of incomplete ossification of the dorsal neural arch of the atlas (IODA) in dogs with atlantoaxial instability (AAI). ANIMALS 106 AAI-affected dogs that underwent ventral fixation of the atlantoaxial joint. PROCEDURES Medical records and CT images for each dog were reviewed. Read More

Objective: Voice alteration as a presenting symptom in cases with Chiari formation is analyzed, as well as outcome after atlantoaxial fixation.

Methods: During the period January 2016 to June 2017, 25 cases of Chiari formation presented with associated or a major presenting symptom of voice or speech quality alteration related to inadequate breathing efforts. All patients underwent atlantoaxial fixation. Read More

Purpose: Mucopolysaccharidosis (MPS) are rare inherited metabolic diseases, causing lysosomal storage of mucopolysaccharides; clinical presentation involves skeletal system and particularly the spine. Anomalies include developing kyphosis at thoracolumbar junction, that can causes nervous symptoms, and dens hypoplasia with associated atlantoaxial subluxation that can cause myelopathy. We present our experience in the treatment of spine pathology in MPS. Read More

Objective: Upper cervical fixation with C2 pedicle screw insertion may predispose patients to vertebral artery injury, in particular, patients with craniovertebral junction anomalies. The aim of this study was to describe an alternative technique with trans-C2 inferior articular process screw (C2IAPS) insertion for rigid C2 fixation, which can be used to anchor the C2 vertebra for upper cervical fixation.

The American Academy of Pediatrics's guideline on health supervision for children with Down syndrome (DS) offers pediatricians guidance to improve detection of comorbid conditions. Pediatrician adherence has not yet been comprehensively evaluated. Medical records of 31 children with DS who received primary care at two urban academic clinic sites from 2008-2012 were reviewed. Read More

Objective: We sought to develop a new posterior fusion technique composed of bilateral C1 titanium cables and C2 pedicle screw-rods for treatment of atlantoaxial instability not suitable for C1 screw placement.

Methods: A study was conducted of 18 patients with atlantoaxial instability who had C1 broken screw trajectory or anatomic anomalies. All patients underwent posterior fixation with bilateral C1 titanium cables and C2 pedicle screws. Read More

Objectives: Canine ventral atlantoaxial stabilization methods have been constantly evolving over the past few decades. Yet, proper experimental data comparing the feasibility and biomechanical properties of currently available surgical options are lacking. The aims of this study were (1) to describe and compare the safety profiles and biomechanical properties of three ventral atlantoaxial stabilization methods; and (2) to test whether recently reported optimal implant definitions constitute reasonable guidelines. Read More

Down syndrome (DS) is a clinical syndrome comprising typical facial features and various physical and intellectual disabilities due to extra genetic material on chromosome 21, with one in every 1000 babies born in the United Kingdom affected. Patients with Down syndrome are at risk of atlantoaxial instability (AAI). Although AAI can occur in other conditions, such as rheumatoid arthritis, this position statement deals specifically with patients with DS and asymptomatic AAI. Read More

Background: Atlantoaxial dislocation (AAD) is the most common craniovertebral junction malformation (CVJm) which are anomalies of the bones and soft tissues surrounding the foramen magnum. It usually leads to neurologic abnormalities because of instability of this mobile area. But vertebral artery dissection (VAD) caused by AAD is uncommon. Read More

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Case: A 35-year-old man was involved in a motor-vehicle collision and sustained multiple thoracoabdominal and extremity injuries. A high injury burden and a normal neurologic examination contributed to a delay in diagnosing a ligamentous, combined atlanto-occipital dissociation (AOD) and vertical atlantoaxial injury (AAI). Additional imaging revealed the combined injury, and the patient underwent an occipitocervical fusion. Read More

Authors:

Department of Neurosurgery, All India Institute of Medical Sciences (AIIMS), New Delhi, India.

Introduction: Congenital disorders of the craniovertebral junction (CVJ) include a wide range of conditions, such as Chiari malformation (CM), basilar Invagination (BI), and atlantoaxial dislocation (AAD). The objective of this paper is to critically review the literature related to the management of congenital CVJ disorders focusing on: the significant developments in the past (from anterior open ventral decompression to modern CVJ realignment); the diagnosis of CVJ instability; the role of atlantoaxial fixation without posterior fossa decompression in patients with tonsillar herniation and no evidence of CVJ instability; use of C1-2 inter-articular spacers and use of C1-2 interarticular spacers with intra-operative manipulations to correct BI with AAD along with its deformity.

Materials And Methods: We performed a review of articles showing up on PubMed database without time restriction. Read More

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Department of Neurosurgery, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany.

Objective: We report on our experiences of navigated posterior C1-C2 spondylodesis in the elderly (≥ 70 years of age).

Patients: This retrospective cohort study evaluated all patients ≥ 70 years of age treated with navigated posterior spondylodesis C1-C2 (at the most to C3) from 2008 to 2015 with a minimum follow-up of 1 year. Minor and major complications within 30 days after surgery, patient outcome, and the rate of solid fusion in computed tomography were recorded. Read More

Objective: This study aimed to evaluate the accuracy of screw placement and clinical outcomes in patients undergoing occipitocervical fusion.

Methods: Patients who underwent occipitocervical fusion with O-arm-based navigation were retrospectively reviewed between January 2015 and December 2017. The patients' characteristics, clinical and radiographic outcomes, and surgical complications were recorded and analyzed. Read More

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Background: There are several techniques for treating atlantoaxial instability, including the Magerl transarticular screw fixation and the Harms/Goel C1-C2 screw rod techniques. Here, we present a novel technique utilizing a polyaxial screw rod system and a combination of C1 lateral mass and C1-C2 transarticular screws.

Several types of atlantoaxial instability can justify surgical fixation. The instrumented fusion procedure described by Harms with screw fixation of the C1 lateral masses and C2 pedicles is a demanding technique that provides lasting stabilization. However, it has been associated with nerve and vascular complications due to the local anatomical configuration. Read More

Background: Postoperative dysphagia is a known complication of anterior cervical surgery, but its incidence and possible mechanisms are seldom reported after occipitocervical fusion (OCF). Our objective was to study the relationship between craniocervical alignment and the development of dysphagia after OCF for the treatment of basilar invagination with atlantoaxial instability.

Methods: The study consisted of a retrospective series and a prospective series. Read More

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Department of Neurosurgery, Spine and Spinal Cord Research Institute, Yonsei University College of Medicine, Severance Hospital, Republic Seoul, Republic of Korea. Electronic address:

VA anomalies in extra- and intraosseous regions of the craniovertebral junction (CVJ) is considered very carefully during the posterior screw fixation for the atlantoaxial instability (AAI). This study aims to compare the incidence and variations of VA anomalies, isthmus and pedicle size of C2 in 100 patients with AAI due to congenital skeletal anomaly (CSA) and acquired disease by using three-dimensional CT angiograms (3D CTA) before surgery. The CSA group contained 48 patients and the acquired disease group consisted of 52. Read More

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The pathology in congenital atlantoaxial instability is usually in C1-2 joints. Addressing the joints appears to be the most rationale approach. The joints are usually approached posteriorly, manipulated, and fused. Read More

Methods: The study group comprised 41 patients without RA who underwent OAF due to AAI. Fifteen patients with postoperative ASD after OAF were classified as the ASD group, and the other 26 patients without postoperative ASD were included in the non-ASD group. Read More

Background: Although C1-C2 pedicle screw techniques have been extensively reported in pediatric series, reports on their use have examined only small series with short follow-up periods. The aim of this study was to report pediatric patients with atlantoaxial rotatory dislocation treated with these techniques with a minimum 5-year follow-up.

Methods: Retrospective review was performed of 27 pediatric patients with atlantoaxial rotatory dislocation who underwent C1-C2 pedicle screw fixation between 2004 and 2012. Read More

Background Context: In patients with mucopolysaccharidosis (MPS), glycosaminoglycan deposits in the dura mater and supporting ligaments cause spinal cord compression and consecutive myelopathy, predominantly at the craniocervical junction. Disease characteristics of craniocervical stenosis (CCS) in patients with MPS differ profoundly from other hereditary and degenerative forms. Because of high periprocedural morbidity and mortality, patients with MPS pose a substantial challenge to the inexperienced medical care provider. Read More

Purpose: Retro-odontoid pseudotumor is common in elderly people and is a cause of cervical myelopathy. The goal of the study was to investigate surgical procedures, outcomes, and post-operative spontaneous regression of posterior cervical retro-odontoid pseudotumors.

Methods: The subjects were 29 patients who underwent surgery for myelopathy due to a retro-odontoid pseudotumor around the craniocervical region at 9 facilities and were followed-up for an average of 54 months (range 12-96 months). Read More

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Background: The involvement of the cervical spine in rheumatoid arthritis (RA) continues to be of clinical importance even in this age of biologics. Pathophysiological changes begin with an isolated atlantoaxial subluxation and may progress to a complex craniocervical and subaxial instability. The onset of cervical myelopathy can occur at any time and leads to a deterioration of the prognosis for the patient. Read More

Authors:

The purpose of this report is to describe the evaluation and treatment of a patient with neck pain and ankylosing spondylitis who had underlying atlantoaxial instability. The patient was a 31-yr-old man diagnosed with ankylosing spondylitis 1 yr prior who was referred to a physical therapist for the treatment of chronic, worsening low back and hip pain. He also had secondary complaints of neck, upper back, and shoulder pain. Read More